1. Field of the Invention
This application relates to a scanner, and more particularly, to solid state waveguide scanner.
2. State of the Prior Art
Various printing systems are known in which a modulated light beam is scanned across a receiving medium. Mechanical deflection devices, such as polygon scanners or galvanometers, can be used to direct the light beam onto the receiving medium. Although these devices are generally satisfactory for many applications, there is a need in the art to increase the speed of operation of the devices and to achieve greater pixel density. In response to these needs, solid state deflection devices have been developed. Such devices include devices using LED's to expose a recording medium and devices using electro-optic elements which have a plurality of individually addressable electrodes for controlling the passage of light.
In the patent to Sprague, U.S. Pat. No. 4,389,659, there is shown a scan printer which includes a multi-gate light valve comprising an electro optic element, and a plurality of separately addressable electrodes coupled to the electro-optic element. A sheet like collimated beam is transmitted through the electro optic element, and an information signal is selectively applied to the electrodes to control the light which is transmitted to a receiving medium. A problem with this printer is that the output power of the light source is effectively divided among the many picture elements required to define a line of the image. If the data samples are short lived, there may be insufficient energy available at one or more picture element positions to adequately expose the receiving medium. Thus, complex circuitry is necessary to maintain the data samples for each line of the image on the electrodes for a period of time sufficient to expose the recording medium.